Experimental compound potent against hepatitis C

CHICAGO (Reuters) - An experimental Bristol-Myers Squibb compound called BMS-790052 is proving to be the most potent yet at treating hepatitis C, an infection poorly treated with existing drugs, company researchers said on Wednesday.

An early, phase I safety study of the compound found it was highly effective at blocking the protein NS5A, a new target that might provide one more weapon against a virus that can quickly develop resistance.

"A lot like HIV, it is anticipated that a combination of at least three drugs will be required to prevent the emergence of resistance," said Bristol-Myers Squibb's Nicholas Meanwell, who worked on the study published in the journal Nature.

"We are targeting a different protein. This will provide a unique resistance profile," Meanwell said in a telephone interview.

Hepatitis damages the liver, causing chronic liver problems, liver cancer, cirrhosis and death.

It is the leading cause of liver disease worldwide, affecting an estimated 3.2 million people in the United States alone and 170 million worldwide.

Typical treatment involves 52 weeks of interferon plus the antiviral drug ribavirin. The combination works in only about half of all patients, and some develop such taxing side effects that they have to stop.

The Bristol-Myers compound works differently than a new class of drugs called protease inhibitors being developed by Merck's Schering-Plough division and Vertex Pharmaceuticals Inc .

SUPPRESSING VIRAL LOAD

Meanwell said BMS-790052 helps inhibit the hepatitis C virus from replicating.

Infected patients who got a single 100 milligram dose of the compound saw their viral load -- a measurement of the virus in their blood -- drop more than 99.9 percent.

Early results of a phase II study presented last week at the European Association for the Study of the Liver in Vienna were also promising. Seven out of eight patients who got the highest dose of the drug had undetectable levels of the virus. The eighth patient had stopped taking the drug for a while.

"It's got potency and effectiveness in a single dose that is unmatched by anything else," Meanwell said.

He said the findings are very early, but the hope is that the compound could be used in a cocktail of drugs to keep the virus from developing resistance long enough for patients to clear the disease.

"The data we've seen so far is extremely encouraging," he said.

New treatments for hepatitis C infection have drawn much attention on Wall Street.

Vertex Pharmaceuticals' experimental hepatitis C treatment telaprevir, which is expected to have phase III results in the third quarter of this year, is projected to have peak U.S. sales of $3.9 billion in 2013, if it wins U.S. approval as expected in the first half of 2011.